How to iterate Lua table from end?

Also you can use standard for statement with reversed index:

for i=1, #mytable do
   print(mytable[#mytable + 1 - i])
end

Thank you, @Piglet, for useful link.

local function reversedipairsiter(t, i)
    i = i - 1
    if i ~= 0 then
        return i, t[i]
    end
end
function reversedipairs(t)
    return reversedipairsiter, t, #t + 1
end

Actually, I figured out an easier way may be to

local mytable = {'a', 'b', 'c'}
for i = #mytable, 1, -1 do
    value = mytable[i]
    print(i .. ": " .. value)
end